One of the primary goals in the field of food sciences, in particular with the area of industrial mass food production, is maintaining the best fidelity to the features of the natural product. This is not an easy task, since many of the processes and additives that permit a high yield at an industrial level are precisely those that alter the original features of the food product, thus leading to an optimization process where one is obligated to choose between yield in the process or fidelity to the natural product.
In the field of fruit pulps, much research and development has taken place with the purpose of maintaining the original taste qualities of recently extracted pulp. The recently extracted pulp tastes like fresh fruit pulp made at home, and maintains the physiochemical characteristics of the fruit. On the contrary, when the pulp is subject to freezing and concentration (which is typical in the prior art), its taste and physicochemical characteristics vary, and the texture of the juice as the end product is degraded, thus lowering the final quality of the product. For purposes of this document, it is important to establish the difference between fruit pulp and fruit juice. The pulp is the material extracted directly from the fruit, which normally is mixed with water or another liquid to drink (i.e. most consumers do not consume the pulp directly). The juice is precisely this blend of the pulp with water, in other words, the end product for the consumer.
When the fruit is peeled or opened, the pulp suffers almost immediately from biological degradation caused by various factors, which makes it especially hard to process, transport, or store at an industrial level, especially at room temperature. One of the most important problems is the oxidation process. In the presence of light and oxygen, the pulp's natural flavor becomes bitter and at the same time turns to the color brown which gives it an unacceptable appearance. Various solutions have been proposed in the prior art to resolve or slow down this process, e.g., concentration of the fruit pulp, freezing or refrigeration, addition of chemical preservatives, and the reduction of oxygen in the final packaging. However, a satisfactory product that has high fidelity for home extracted fruit pulp and that avoids the oxidation process without the need for concentrating or refrigerating has not been obtained.
Alteration of the fruit pulp by microbiological action also exists. Recently extracted fruit pulps contain numerous microorganisms of different types (bacteria, molds and yeasts). The first microbiological alteration that can be occur quickly at room temperature is alcohol fermentation, which is caused by different yeasts and in some cases accompanied by superficial proliferation of molds and of lactic fermentation. For this reason, recently extracted fruit pulp must be considered an extremely perishable article. Solutions for this problem in the art of food preservation generally include the use of preservatives of wide commercial use, such as sodium benzoate and potassium sorbate, as well as refrigeration and concentration.
At industrial production levels, additional problems also exist for the processing of the fruit pulp or its byproducts. One of them is maintaining homogeneity in the final product, since it is natural for variations to exist within different batches of fruit used to provide the raw material for the pulp, particularly where different species of fruits are used, or when they come from different geographical zones. Two key variable characteristics are the acidity, measured in pH, and the sugar levels, also known as the "Brix level". The acidity is typically leveled with the introduction of citric acid. The sugar level is leveled with the sucrose, fructose, or glucose.
Another problem that presents itself at the industrial level is that of maintaining a continuous and well preserved source of fruit. Many times it is necessary to import the fruit or the pulp from different regions with the purpose of satisfying the market demand, which also implies the adequate preservation of this fruit or pulp during its transportation and storage. The worldwide renowned solution for this problem has been to use the concentrated and/or frozen pulp as the raw material. The concentrated or frozen pulp permits easier handling, and at the same time provides a homogenous source at the moment of reconstituting the concentrate so as to once again obtain the pulp. At an industrial level, a production plant is more efficient when it uses concentrated or frozen pulp, instead of obtaining its own fruits and processing them. The concentrated and frozen pulp is easy to come about, is always available, especially where futures markets exist for this commodity. The pulp concentrate is produced by one of the various concentration processes well known in the state of the art (for example, low pressure evaporation). In theory, the dilution of a good fruit pulp with the adequate amount of water should provide a product equal to fresh made juice. The reality is very different because of the alterations that happen during its production and storage, which naturally affect the taste properties of the pulp considerably. For example, the concentration process almost always implies a thermal evaporation process, which subjects the pulp to temperatures that without a doubt induce important chemical changes. Alternatively, the darkening process is also more problematic in the case of concentrates and implies the use of refrigeration or chemicals to counteract it. The use of concentrates also makes it impossible for the maker of the product to regulate the initial flavor and texture of the recently extracted pulp, which is a critical aspect if one desires to reproduce pulp freshly obtained at home. Obviously, if one desires to reproduce a home made pulp, the process for making freshly made pulp at home must be simulated; however, it is common for concentrate manufacturers to tend to make good use of the capacity of their machines to practice an excessive extraction that allows yield improvement, but with adverse effects to the taste properties and the stability of the pulp. No suggestion nor teaching exists in the state of the art, in relation to the industrial production of pulps, to go directly from the recently extracted pulp to the packaging process, and moreover, the opposite seems suggested: it is almost mandatory to use frozen pulp or concentrate as a raw material for reasons of efficiency and convenience.
Another serious problem that results during industrial level production is the degradation of the pulp's texture as a final product. The natural texture of the juice, known as mouthfeel, must reflect a certain quantity of solids that are normally present in the pulp after the fruit is extracted. A great portion of the texture degradation occurs during the freezing of the concentrate (for its transportation and storage), which causes rupture in the cellular walls of the pulp's compounds, thus seriously affecting the texture of the final juice. The rest of the degradation is the result of the use of mixers, pumps, and filters during the production process. A known solution to give back the original texture to the juice is the latter addition of pulp, with the purpose of trying to recreate the natural mouthfeel created by the presence of solids in a defined ratio. (For example, see U.S. Pat. No. 5,260,086--for orange juices). Degradation of the frozen pulp or concentrate also exists at the level of colloidal alterations, by means of which the concentrate's elevated viscosities can give way to gelatination phenomenon, which of course results in the loss of all of its commercial value. This last type of degradation can be avoided with the addition of chemicals such as sodium citrate, or through the inactivation of pectolytic enzymes by thermal processes.
The conventional commercial presentation of the fruit pulp is a package, typically refrigerated or frozen, that contains a large serving, in other words, for 4 or more glasses of juice. To prepare the juice, the consumer must mix the pulp in water (or other liquid, such as milk), and in many cases a blender is used given the frozen state of the pulp. The majority of consumers consider that it is only worthwhile to prepare juice (in other words, mix the pulp with water) when various glasses will be prepared and not only one. Likewise, this juice is normally only prepared where it is possible to maintain the pulp refrigerated, and where methods exist for mixing the pulp with water. In other words, the conventional fruit pulp package does not allow the consumer to carry an individual portion of pulp (say in her pocket) and to mix it easily with water at any time of day.